From the patch notes:

Dragonknight
Ardent Flame
- Fiery Grip: Switched the position of this ability with the Lava Whip ability as seen in the skill line UI.
- Lava Whip: Switched the position of this ability with the Fiery Grip ability as seen in the skill line UI.

So I assume that's another "feature" or change that ZOS' developers were not able to think through properly and see problems in advance.

Issue:
After the patch, many DK players (including myself) report that the Fiery Grip skill is now at level 1-3 and unmorphed, although it was maxed out (morphed) before the patch.
So as a result we all have to relevel this skill now up to the morph and the morph itself up to level IV.

Possible cause:
The developers didn't think ahead as it should be quite obvious to everyone that a Rank 4 skill (which Fiery Grip now is) requires way more XP to level up as a Rank 1 skill (which Fiery Grip was before the patch).
So I assume, that the developers just switched the positions without adjusting the skill XP for existing DKs out there, resulting in the above mentioned issue. So us DKs did not loose XP, but the level brackets for the skill got boosted up to a rank 4 skill.

I don't know if it is even possible to fix this (as it would mean to adjust the skill Xp for DKs out there for this particular skill) but this issue is just another one that shows that ZOS' developers are not thinking far ahead as this issue should have come to their mind immediately when they discussed the topic of switching skill positions internally.

Sorry, but issues like this happen to amateur programmers, come on ZOS...